[PATCH 5.17 0675/1126] can: isotp: return -EADDRNOTAVAIL when reading from unbound socket

Greg Kroah-Hartman
2022-04-05T08:36:18Z

From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit 30ffd5332e06316bd69a654c06aa033872979b7c ]

When reading from an unbound can-isotp socket the syscall blocked
indefinitely. As unbound sockets (without given CAN address information)
do not make sense anyway we directly return -EADDRNOTAVAIL on read()
analogue to the known behavior from sendmsg().

Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Link: https://github.com/linux-can/can-utils/issues/349
Link: https://lore.kernel.org/all/20220316164258.54155-2-socketcan@hartkopp.net
Suggested-by: Derek Will <derekrobertwill@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/can/isotp.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/can/isotp.c b/net/can/isotp.c
index f8e3aeb79e3f..8966f06e0660 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1005,12 +1005,16 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
+ struct isotp_sock *so = isotp_sk(sk);
int err = 0;
int noblock;

noblock = flags & MSG_DONTWAIT;
flags &= ~MSG_DONTWAIT;

+ if (!so->bound)
+ return -EADDRNOTAVAIL;
+
skb = skb_recv_datagram(sk, flags, noblock, &err);
if (!skb)
return err;
--
2.34.1